Can't enable Advanced Data Protection for iCloud on an iPhone 12 Pro Max

[lsquare]

I can't figure out why I can't enable 2FA on my second account from my IP12PM. I do use two iOS accounts and switch back and forth on this phone. My first account already has 2FA, but the second one doesn't. When I tried to set up 2FA, it told me the phone number that I want to use is already used. Does that mean I can't use one phone number with multiple Apple IDs? The second account is currently overcapacity (23GB) as I let my iCloud+ subscription lapsed. Not sure what other details I'll need to provide to get to the bottom of this. Help?

 

[FreakinEurekan]

You can use the same Trusted Number on more than one 2FA account, but not infinitely. It will at some point tell you that you need to use a different number. Doesn't seem to be a simple formula; the logic takes a lot of factors into account and switching back & forth on one device might be a factor.

 

[lsquare]

You can use the same Trusted Number on more than one 2FA account, but not infinitely. It will at some point tell you that you need to use a different number. Doesn't seem to be a simple formula; the logic takes a lot of factors into account and switching back & forth on one device might be a factor.

So how do I figure out what's causing the problem?

 

[FreakinEurekan]

You… use a different phone number.

 

[lsquare]

You… use a different phone number.

How do you know it's my phone number that's causing the problem?

 

[FreakinEurekan]

I'm making an assumption, since you didn't give a verbatim error message. But the error I'm thinking of is something along the lines of "This phone number has been used too many times, use a different one." If that's basically what it's saying then.... use a different phone number.

If the error isn't that, tell us what it IS and we'll see if you get other advice.